Low Fuel Level
Certain OBD II compliant ECMs receive the low fuel level input signal from the instrument cluster. The signal is processed by the instrument cluster and used to illuminate the low fuel warning indicator. At the same time the signal is sent to the ECM as information relating to a possible misfire condition. The low fuel input is stored in the ECM. If a misfire occurs along with a low fuel level, the lack of fuel supply could be the cause for the misfire.
The signal to the ECM is a digital switched high/low input that is switched low with a low fuel indication.